In adrenocortical insufficiency, such as Addison disease, the most severe manifestations are the result of: a. An insufficient amount of T4 and T3
b. Deficiencies in the renin-angiotensin system
c. An insufficient amount of circulating cortisol
d. Decreased levels of all the adrenocortical hormones

The correct answer is C. An insufficient amount of circulating cortisol

Explanation:

The main cause of adrenocortical insufficiency is the lack of production and circulation of hormones, especially of cortisol (steroid hormone). Moreover, the lack of cortisol is caused by damages in the adrenal glands. Besides this, this insufficiency leads to conditions such as Addison disease, which is associated with symptoms such as nausea, fatigue, dizziness, and can be life-threatening. According to this, the correct answer is option C considering insufficiency cortisol plays a major role in this condition.

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